diff options
author | NeilBrown <neilb@suse.de> | 2010-05-22 08:31:36 +1000 |
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committer | NeilBrown <neilb@suse.de> | 2010-05-22 08:31:36 +1000 |
commit | 19fdb9eefb21b72edbc365b838502780c392bad6 (patch) | |
tree | deae04c48532d6eab64ed4b0396737bb854b5506 /Documentation/sound/alsa/HD-Audio.txt | |
parent | be6800a73aa2f3dc14744c3b80e676d189789f04 (diff) | |
parent | 3ff195b011d7decf501a4d55aeed312731094796 (diff) |
Merge commit '3ff195b011d7decf501a4d55aeed312731094796' into for-linus
Conflicts:
drivers/md/md.c
- Resolved conflict in md_update_sb
- Added extra 'NULL' arg to new instance of sysfs_get_dirent.
Signed-off-by: NeilBrown <neilb@suse.de>
Diffstat (limited to 'Documentation/sound/alsa/HD-Audio.txt')
-rw-r--r-- | Documentation/sound/alsa/HD-Audio.txt | 20 |
1 files changed, 15 insertions, 5 deletions
diff --git a/Documentation/sound/alsa/HD-Audio.txt b/Documentation/sound/alsa/HD-Audio.txt index f4dd3bf99d1..bdafdbd3256 100644 --- a/Documentation/sound/alsa/HD-Audio.txt +++ b/Documentation/sound/alsa/HD-Audio.txt @@ -119,10 +119,18 @@ the codec slots 0 and 1 no matter what the hardware reports. Interrupt Handling ~~~~~~~~~~~~~~~~~~ -In rare but some cases, the interrupt isn't properly handled as -default. You would notice this by the DMA transfer error reported by -ALSA PCM core, for example. Using MSI might help in such a case. -Pass `enable_msi=1` option for enabling MSI. +HD-audio driver uses MSI as default (if available) since 2.6.33 +kernel as MSI works better on some machines, and in general, it's +better for performance. However, Nvidia controllers showed bad +regressions with MSI (especially in a combination with AMD chipset), +thus we disabled MSI for them. + +There seem also still other devices that don't work with MSI. If you +see a regression wrt the sound quality (stuttering, etc) or a lock-up +in the recent kernel, try to pass `enable_msi=0` option to disable +MSI. If it works, you can add the known bad device to the blacklist +defined in hda_intel.c. In such a case, please report and give the +patch back to the upstream developer. HD-AUDIO CODEC @@ -196,7 +204,6 @@ generic parser regardless of the codec. Usually the codec-specific parser is much better than the generic parser (as now). Thus this option is more about the debugging purpose. - Speaker and Headphone Output ~~~~~~~~~~~~~~~~~~~~~~~~~~~~ One of the most frequent (and obvious) bugs with HD-audio is the @@ -592,6 +599,9 @@ probing, the proc file is available, so you can get the raw codec information before modified by the driver. Of course, the driver isn't usable with `probe_only=1`. But you can continue the configuration via hwdep sysfs file if hda-reconfig option is enabled. +Using `probe_only` mask 2 skips the reset of HDA codecs (use +`probe_only=3` as module option). The hwdep interface can be used +to determine the BIOS codec initialization. hda-verb |